Rheumatoid factor (RF) is an immunoglobulin initially described in association with rheumatoid arthritis. It is an IgM antibody against the FC portion of the IgG antibodies. Ongoing research has identified a group related immunoglobulins, classed as rheumatoid factors (RFs) and despite extensive investigation, the exact mechanisms of action, role in normal physiology and pathological effects are still largely unknown.
Although originally described in 1940 as a traditional marker for rheumatoid arthritis, rheumatoid factor is known to be non-specific, found in 70-90% of patients with rheumatoid arthritis . It is also associated with numerous autoimmune and chronic infectious diseases such as :
- connective tissue disorders